I have a constant in my class in gdextension as such:

class MyCustomClass : public Node2D
{
    GDCLASS(MyCustomClass, Node2D);

    public:
        const Vector2 MY_VECTOR = Vector2(100, 100);
        ...

}

how do I bind it in _bind_methods() as done for properties?

void MyCustomClass::_bind_methods()
{
   ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "my_variable"), "set_my_variable", "get_my_variable");
}

I’m trying to achieve this in such a way that they are exposed in gdscript